Strain viewers have for long been used in the GLASS INDUSTRY for the examination of a wide range of glass products to determine the residual stresses in them. Strain Viewers can be supplied for either qualitative or quantitative analysis, but of late, it has become more important to have quantitative measurements when setting quality standards.
In the past few years Strain Viewers have become increasingly popular within the PLASTICS INDUSTRY.
: flat, automotive, container glassware, domestic glassware, scientific glassware, pharmaceutical glassware, tubular glassware, television and cathode ray tubes, illuminating glassware etc.
: PET bottles and preforms, compact discs, injection moulded
components, acrylic sheets, plastic bags, film etc.
In fact, Strain Viewers can be used to examine any glass or plastics products which are transparent.
Types of Strain Viewers available:
There is a wide range of Strain Viewers to suit all applications, eg, On-Line, Large Field etc. A selection of the most popular Strain Viewers are shown below :
- General Purpose – can be applied to the quality control inspection of glass and plastics components and may be employed as a vertical or horizontal viewing instrument. The working space available within the unit enables a wide variety of components to be accommodated for hand held examination in polarised light.
- Edge Stress – a portable instrument which allows quantitative measurements to be of stresses at the edges of glass sheets by employing the Senarmont (or Friedel) method of compensation. Amongst the applications are the measurements of edge stresses in: laminated glass sheets; e.g. Windshields, Safety windows, Toughened or tempered glass, Heat-Strengthened glass.
- Compact – this Strain Viewer has been developed specifically for the inspection of stresses in small glass components such as light bulbs, precision glassware, ampoules and miniature bottles and jars.
- PET Preforms – for crystallinity and other defects. This Strain Viewer is already in world-wide use for the quality control of PET preforms. The advantages of the product are: 1.) crystallinity is readily identified; 2.) Not only can the molecular birefringent flow lines (fringes) be seen in colour, but the black isoclinic lines are visible when the preform axis are parallel to the polarising axis of the viewer. The isoclinic lines indicate the directions of the molecular orientational strains; 3.) A special and removable stage is provided to rapidly obtain the correct alignments of the preforms when viewing. For observations of the fringes the preforms are aligned at 45 degrees to the polarising axis and at 0 degrees to view the black isoclinics. This stage also allows for the rotation of the preforms whilst viewing. Sodium and white light are used for the examination of coloured preforms or completed bottles.
- Adjustable – can be used for the quality control of glass components, can be tilted to 180 degrees and the distance between the two polarising screens can be adjusted as required to accommodate glass of differing sizes.
- Senarcom– fitted with magnifier lens, with 200mm diameter field of view.’ The Senarcom’ Strain Viewer enables qualitative and quantitative assessments to be made of the stresses and strains in transparent bottles, precision glassware and other glass or plastics products. The stress or strain magnitudes in the component under examination can be accurately measured using the Senarmont method of compensation.
Depends on your custom application.